This is the second 4013TSW I've seen that has a slide stop that seems to be chafing or at least marring the slide. I checked my 4003TSW thinking it may be common but the slide doesn't even come close to the stop.

The 4013 in the picture below is supposed to be like new, and otherwise it does look as new, but seeing this on two near pristine 4013TSW pistols recently is strange. The 3913TSW uses a slide stop with the upper part cut away but the 4013 and 4003TSW does not, is this something specific to the 4013TSW?



Anyone know what's going on here?

I had a 645 that had that same issue. Turns out, the slide stop was slightly bent and worn. It was an old gun so I get the worn, but the bent part, who knows... A new slide stop solved the problem on that gun. I was suprised to see how little engagement there was before the stop slipped over the slide and left the mark.

So in your opinion it definitely looks like slide to slide stop contact in the above picture? How the area on the slide behind the stop - where the rear arrow is pointing - got marred/worn is a mystery to me since the slide stop has to be removed for the slide to move that far forward.

Mine was getting marked up from the rear part of the slide stop. Your gun may be doing it on the front portion, but without seeing it in person, I am at a loss. Mine marked from the notch where the slide stop locks it forward to the end of travel during recoil. Yours does look like it goes all the way to the front, so I have no idea...

The slide stop is bent. Replace it. Brownells and S&W have brand new slide stops.

This is the first time I've heard of a slide stop bending.
For the record the 4013TSW in the photo isn't mine, it's one I was considering buying.
Thanks all.

the slide stop does not bend with time, its likely not perfectly straight.

I once owed a 4013TSW and the frame width is slighly wider than the slide.

could those marks be caused by something else??????

guns get marked up with use unless you handle with a swadling cloth and dont shoot.

shoot away....if the marking is identified coming from the slide lock lever....call SW for a replacement.

I repeat the slide stop is bent. I have two used 645's where at one time or another the slide stop has been replaced because of this issue.

I contacted the seller and he said the area in question is "glare."
I'm a little skeptical.

Well, to me it looks like the mark towards the rear was made when someone installed the slide stop incorrectly - pushing in on the slide stop when it was not fully seated and slightly raised, and letting the slide run forward a little bit, causing the "tab" on the slide stop to rub against the slide and making that mark. I can neither confirm nor deny that I may or may not have made a similar mark on a pistol or two doing that very thing

The mark towards the muzzle I don't know. I can't even really see it from the photo provided. Maybe it is glare?